Internal combustion engine

An internal combustion engine comprising:

• fuel injection means for injecting a gasoline fuel into a combustion chamber which is defined by a top surface of a piston, a bore wall surface of a cylinder, and a bottom surface of a cylinder head of the internal combustion engine;
• and
• premixed-charge compression auto-ignition combustion operation execution means for, when the internal combustion engine is operated in a light-load region, premixing air taken into the combustion chamber and the fuel injected into the combustion chamber from the fuel injection means, and forming and compressing a homogeneous air/fuel mixture having uniform spatial distribution of the fuel to thereby initiate auto-ignition combustion of the fuel;
• the internal combustion engine further comprising diffusion combustion operation execution means for, when the internal combustion engine is operated in a high-load region in which load is greater than in the light-load region, compressing air taken into the combustion chamber within the combustion chamber and injecting the fuel into the compressed air from the fuel injection means to thereby initiate diffusion combustion of the fuel in place of the auto-ignition combustion of the fuel.